[Relation between chronic urticaria and thyroid autoimmunity]

ABSTRACT

Chronic urticaria is a tormenter and does not have a known etiology. Association between chronic urticaria and thyroid auto-immunity has shown different results. The aim of this study is to evaluate the effect of Levo-thyroxine on the chronic urticaria and association between chronic urticaria with thyroid auto-immunity. In a prospective case-control study, we compared the frequency of thyroid auto antibodies in 60 patients [all females, with exception of six males, ages 15 to 60 years] with chronic urticaria and compared with 60 mached age healthy volunteers. All cases with chronic urticaria and control group were normal CBC, antinuclear antibodies, rheumatoid factors, complement, stool exam, liver function test [LFT], kidney function and skin prick test, prior to being referred to us. We performed thyroid auto antibodies, thyroid hormones and IgE antibodies before treating all subjects. Half of them with positive anti-thyroid antibody [n=11], received Levo-thyroxine [100 micro g] daily for 1 month and the remaining half [n=11] were control group. The frequency of thyroid auto antibodies was significantly higher in patients with chronic urticaria than in healthy control [36.6% vs. 9%; p<0.01]. All patients were euthyroid, however, one was found to have increased anti-thyroid antibody levels with sub clinical hypothyroidism [TSH increased, low T4]. Total serum IgE increased in ten cases of patients group [16.6%] compared with six control groups [10%]. Nine patients [40%] had complete response, five patients [30%] had partial response and five patients [30%] did not show any response to treatment compared with control group, in which complete and partial resolution was 30% and others with no resolution. Chronic urticaria may be associated with thyroid disorders [positive anti- thyroid antibodies] despite normal thyroid function test. For chronic urticaria despite increase serum IgE level with unknown origin, must be evaluated by a thyroid function test, along with anti -thyroid antibodies and treatment if necessary